The AD Active Directory is a database to store enterprise-wide configuration
information for entities such as

User information such as name, password,
etc.

Group information such as name, membership,
etc.

Computer information such as name, role,
etc.

Printer information such as name, driver,
queue, etc.

Information about individual users, groups,
etc. are represented by objects in the database. An object is like a database
record.

Attributes are the characteristics of an entity
such as name, password, membership, driver, etc.

The AD schema defines the each object type and
its attributes. The schema is stored in the AD database and can be extended and
modified.

The directory acts as the yellow pages
for network resources. Resources are advertised by publishing related objects in
the directory. Windows clients can query the directory to locate network
resources. Searching can specify specific attributes of a resource, such as

Printers that print color

Printers that support double-sided duplex
printing

Active Directory has many improvements
over NT domains as shown in the following table.